Hi,
I want to achieve following: (convert the input logic query to a standard
format)
(1) a AND b ==> (a and b)
(2) a OR b ==> (a or b)
(3) a OR b AND c ==> (a or (b and c))
By using the Antworks took I know that the lexer and parser grammar works fine
now (It generate the correct AST tree). But the strange thing is that my tree
walker grammar doesn't work. It generate following result:
(1) a AND b ==> (a b and)
(2) a OR c ==> (a b or)
Where am I wrong?
Thx !
-------------------------- Parser ----------------------
grammar Query;
//=== Parser Option ===//
options {
output = AST;
k=*;
}
//=== Lexer ===//
LEFT_PAREN: '(';
NOT: 'NOT';
AND: 'AND';
OR: 'OR';
WORD: ('a'..'z' | 'A'..'Z' | '.' | ',' | '0'..'9')+ | '"'.+'"';
RIGHT_PAREN: ')';
WHITESPACE: (' ' | '\t' | '\r' | '\n') { $channel = HIDDEN; } ;
//=== Parser ===//
expr: orexpression*;
orexpression
: andexpression (OR^ andexpression)*
;
andexpression
: notexpression (AND^ notexpression)*
;
notexpression
: (NOT^)? atom
;
atom
: WORD
| LEFT_PAREN! expr RIGHT_PAREN!
;
------------------ Tree Walker --------------------
tree grammar QueryWalker;
options {
output = AST;
ASTLabelType = CommonTree;
}
expr returns [String value=""]
: (a=orexpression { $value += " " + $a.value;} )+
;
orexpression returns [String value=""]
: ^(AND a=expr b=expr) {
$value = "(" + $a.value + " or " + $b.value + ")";
}
| ^(OR a=expr b=expr) {
$value = "(" + $a.value + " and " + $b.value+ ")";
}
| ^(NOT a=expr) {
$value = "(not " + $a.value +")";
}
| WORD {
$value = $WORD.text;
};
Thx !
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